Use of an alkoxylated polytetrahydrofuran to reduce fuel consumption

ABSTRACT

The use of an alkoxylated polytetrahydrofurane of formula wherein m, m′, n, n′, p, p′ and k are integers in the range of ≧1, R 1  denotes an unsubstituted linear or branched alkyl radical, R 2  denotes —CH 2 —CH 3 , and R 3  denotes a hydrogen atom or —CH 3 , as an additive in a fuel for reducing fuel consumption in the operation of an internal combustion engine with this fuel.

The present invention relates to the use of an alkoxylatedpolytetrahydrofurane of general formula (I)

-   -   wherein    -   m is an integer in the range of ≧1 to ≦50,    -   m′ is an integer in the range of ≧1 to ≦50,    -   (m+m′) is an integer in the range of ≧1 to ≦90,    -   n is an integer in the range of ≧0 to ≦75,    -   n′ is an integer in the range of ≧0 to ≦75,    -   p is an integer in the range of ≧0 to ≦75,    -   p′ is an integer in the range of ≧0 to ≦75,    -   k is an integer in the range of ≧2 to ≦30,    -   R¹ denotes an unsubstituted, linear or branched, alkyl radical        having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,        21, 22, 23, 24, 25, 26, 27 or 28 carbon atoms,    -   R² denotes —CH₂—CH₃, and    -   R³ identical or different, denotes a hydrogen atom or —CH₃,        whereby the concatenations denoted by k are distributed to form        a block polymeric structure and the concatenations denoted by p,        p′, n, n′, m and m′ are distributed to form a block polymeric        structure or a random polymeric structure, as an additive in a        fuel for different purposes.

The present invention further relates to a fuel composition whichcomprises a gasoline fuel, the alkoxylated polytetrahydrofuranementioned and at least one fuel additive with detergent action.

The present invention further relates to an additive concentrate whichcomprises the alkoxylated polytetrahydrofurane mentioned and at leastone fuel additive with deter-gent action.

It is known that particular substances in the fuel reduce internalfriction in the internal combustion engines, especially in gasolineengines, and thus help to save fuel. Such substances are also referredto as lubricity improvers, friction reducers or friction modifiers.Lubricity improvers customary on the market for gasoline fuels areusually condensation products of naturally occurring carboxylic acidssuch as fatty acids with polyols such as glycerol or with alkanolamines,for example glyceryl monooleate.

A disadvantage of the prior art lubricity improvers mentioned is poormiscibility with other typically used fuel additives, especially withdetergent additives such as polyisobuteneamines and/or carrier oils suchas polyalkylene oxides. An important requirement in practice is that thecomponent mixtures or additive concentrates provided are readilypumpable even at relatively low temperatures, especially at outsidewinter temperatures of, for example, down to −20° C., and remainhomogene-ously stable over a prolonged period, i.e. no phase separationand/or precipitates may occur.

Typically, the miscibility problems outlined are avoided by addingrelatively large amounts of mixtures of paraffinic or aromatichydrocarbons with alcohols such as tert-butanol or 2-ethylhexanol assolubilizers to the component mixtures or additive concentrates. In somecases, however, considerable amounts of these expensive solubilizers arenecessary in order to achieve the desired homogeneity, and so thissolution to the problem becomes uneconomic.

The low molecular weight carboxylic acids and carboxylic acidderivatives, glycol ethers and alkylated phenols recommended in WO2007/053787 as solubilizers for such component mixtures or additiveconcentrates are also uneconomic owing to their high feedstock costsand, apart from their function as solubilizers, do not have any furtherpositive effects. On the contrary, they harbor the risk of causingadverse effects, for example undesired oil dilution and increasedformation of combustion chamber depo-sits.

In addition, the prior art lubricity improvers mentioned often have thetendency to form emulsions with water in the component mixtures oradditive concentrates or in the fuel itself, such that water which haspenetrated can be removed again via a phase separa-tion only withdifficulty or at least only very slowly.

For instance, the lubricity improvers described in EP-A 1 424 322 and WO03/070860, which are based on polyisobutenylsuccinimides with mono- orpolyamines or alkanol-amines such as butylamine, diethylenetriamine,tetraethylenepentamine or amino-ethyleneethanolamine, exhibit goodmiscibility with further additive components in corresponding mixturesor concentrates, but have a marked tendency to form stable emulsionswith water, which can lead to the effect that water and soil particlesare entrained into the fuel supply chain and ultimately can also getinto the engine. Water can cause corrosion; soil particles can lead todamage in fuel pumps, fuel filters and injectors.

EP-A 1 076 072 describes certain derivatives of polytetrahydrofurans asfuel deter-gents, i.e. for improving intake valve cleanliness ofinternal combustion engines. Such derivatives of polytetrahydrofuranscan be applied together with other additives with detergent action,however, EP-A 1 076 062 is silent about specifying said other addi-tiveswith detergent action.

Furthermore, EP-A 1 076 072 does not teach to apply such derivatives ofpolytetrahydrofurans as fuel additives for reducing fuel consumption.

It was an object of the present invention to provide fuel additiveswhich firstly bring about effective fuel saving in the operation of aspark-ignited internal combustion engine, and secondly no longer havethe outlined shortcomings of the prior art, i.e. more particularly notremaining homogeneously stable over a prolonged period without any phaseseparation and/or precipitates, poor miscibility with other fueladditives and the tendency to form emulsions with water. In addition,they should not worsen the high level of intake valve cleanlinessachieved by the modern fuel additives.

Accordingly, the use of an alkoxylated polytetrahydrofurane of generalformula (I) as described above as an additive in a fuel for reducingfuel consumption in the operation of an internal combustion engine withthis fuel has been found. Preferably, the said use as an additive in agasoline fuel for reducing fuel consumption in the operation of aspark-ignited internal combustion engine with this fuel or as anadditive in a gasoline fuel for reduction of fuel consumption in theoperation of a self-ignition internal combustion engine with this fuelhas been found.

It can be assumed that the cause of the fuel saving by virtue of thealkoxylated polytetrahydrofurane (I) mentioned is based substantially onthe effect thereof as an additive which reduces internal friction in theinternal combus-tion engines, especially in gasoline engines. Thereaction product mentioned thus functions in the context of the presentinvention essentially as a lubricity improver.

Furthermore, the use of an alkoxylated polytetrahydrofurane of formula(I) as described above as an additive in a fuel for minimization ofpower loss in internal combustion engines and for improving accelerationof internal combustion engines has been found.

Furthermore, the use of an alkoxylated polytetrahydrofurane of formula(I) as described above as an additive in a fuel for improving thelubricity of lubricant oils contained in an internal combustion enginefor lubricating purposes by operating the internal com-bustion enginewith a fuel containing an effective amount of at least one alkoxylatedpolytetrahydrofurane of formula (I) has been found.

It can be assumed that a part of the alkoxylated polytetrahydrofurane(I) mentioned contained in the fuel is transported via the combustionchamber where the additive containing fuel is burnt into the lubricantoils and acting there as a further lubricating agent. The advantage ofthis mechanism is that the said further lubricating agent iscontinuously refreshed by the fuel feeding.

Spark-ignition internal combustion engines are preferably understood tomean gasoline engines, which are typically ignited with spark plugs. Inaddition to the customary four- and two-stroke gasoline engines,spark-ignition internal combustion engines also include other enginetypes, for example the Wankel engine. These are generally engines whichare operated with conventional gasoline types, especially gasoline typesaccording to EN 228, gasoline-alcohol mixtures such as Flex fuel with 75to 85% by volume of ethanol, liquid pressure gas (“LPG”) or compressednatural gas (“CNG”) as fuel.

However, the inventive use of the alkoxylated polytetrahydofuranmentioned also relates to newly developed internal combustion enginessuch as the “HCCl” engine, which is self-igniting and is operated withgasoline fuel.

The instant invention works preferably with direct injection gasolinedriven combustion engines.

Hence, in one embodiment, the presently claimed invention is directed tothe use of an alkoxylated polytetrahydrofurane of general formula (II)

-   wherein-   m is an integer in the range of ≧0 to ≦30,-   m′ is an integer in the range of ≧0 to ≦30,-   (m+m′) is an integer in the range of ≧1 to ≦60,-   k is an integer in the range of ≧2 to ≦30, and-   R¹ denotes an unsubstituted, linear or branched, alkyl radical    having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,    22, 23, 24, 25, 26, 27 or 28 carbon atoms,    whereby the concatenations denoted by k, m and m′ are distributed to    form a block polymeric structure.

Hence, in another embodiment, the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

-   wherein-   m is an integer in the range of ≧1 to ≦30,-   m′ is an integer in the range of ≧1 to ≦30,-   (m+m′) is an integer in the range of ≧3 to ≦50,-   n is an integer in the range of ≧3 to ≦45,-   n′ is an integer in the range of ≧3 to ≦45,-   (n+n′) is an integer in the range of ≧6 to ≦90,-   p is an integer in the range of ≧0 to ≦75,-   p′ is an integer in the range of ≧0 to ≦75,-   k is an integer in the range of ≧3 to ≦25,-   R¹ denotes an unsubstituted, linear or branched, alkyl radical    having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon    atoms,-   R² denotes —CH₂—CH₃, and-   R³ identical or different, denotes a hydrogen atom or —CH₃,    whereby the concatenations denoted by k are distributed to form a    block polymeric structure and the concatenations denoted by p, p′,    n, n′, m and m′ are distributed to form a block polymeric structure    or a random polymeric structure.

Hence, in another embodiment, the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

-   wherein-   m is an integer in the range of ≧1 to ≦30,-   m′ is an integer in the range of ≧1 to ≦30,-   (m+m′) is an integer in the range of ≧3 to ≦50,-   n is an integer in the range of ≧0 to ≦45,-   n′ is an integer in the range of ≧0 to ≦45,-   p is an integer in the range of ≧3 to ≦45,-   p′ is an integer in the range of ≧3 to 45,-   (p+p′) is an integer in the range of ≧6 to ≦90,-   k is an integer in the range of ≧3 to 25,-   R¹ denotes an unsubstituted, linear or branched, alkyl radical    having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon    atoms,-   R² denotes —CH₂—CH₃, and-   R³ identical or different, denotes a hydrogen atom or —CH₃,    whereby the concatenations denoted by k are distributed to form a    block polymeric structure and the concatenations denoted by p, p′,    n, n′, m and m′ are distributed to form a block polymeric structure    or a random polymeric structure.

As used herein, “branched” denotes a chain of atoms with one or moreside chains attached to it. Branching occurs by the replacement of asubstituent, e.g., a hydrogen atom, with a covalently bonded alkylradical.

“Alkyl radical” denotes a moiety constituted solely of atoms of carbonand of hydrogen.

The inventively claimed alkoxylated polytetrahydrofuranes are oilsoluble, which means that, when mixed with mineral oils and/or fuels ina weight ratio of 10:90, 50:50 and 90:10, the inventively claimedalkoxylated polytetrahydrofuranes do not show phase separation afterstanding for 24 hours at room temperature for at least two weightrations out of the three weight ratios 10:90, 50:50 and 90:10.

Preferably the alkoxylated polytetrahydrofurane has a kinematicviscosity in the range of ≧200 mm²/s to ≦700 mm²/s, more preferably inthe range of ≧250 mm²/s to ≦650 mm²/s, at 40° C., determined accordingto ASTM D 445.

Preferably the alkoxylated polytetrahydrofurane has a kinematicviscosity in the range of ≧25 mm²/s to ≦90 mm²/s, more preferably in therange of ≧30 mm²/s to ≦80 mm²/s, at 100° C., determined according toASTM D 445.

Preferably the alkoxylated polytetrahydrofurane has a pour point in therange of ≧−60° C. to ≦20° C., more preferably in the range of ≧−50° C.to ≦15° C., determined according to DIN ISO 3016.

Preferably the alkoxylated polytetrahydrofurane has a weight averagemolecular weight Mw in the range of 500 to 20000 g/mol, more preferablyin the range of 2000 to 10000 g/mol, most preferably in the range of2000 to 7000 g/mol, even more preferably in the range of 4000 to 7000g/mol determined, determined according to DIN 55672-1.

Preferably the alkoxylated polytetrahydrofurane has a polydispersity inthe range of 1.05 to 1.60, more preferably in the range of 1.05 to 1.50,most preferably in the range of 1.05 to 1.45, determined according toDIN 55672-1.

Preferably k is an integer in the range of ≧3 to ≦25, more preferably kis an integer in the range of ≧3 to ≦20, most preferably in the range of≧5 to ≦20, even more preferably in the range of ≧6 to ≦16.

Preferably m is an integer in the range of ≧1 to ≦25 and m′ is aninteger in the range of ≧1 to ≦25, more preferably m is an integer inthe range of ≧1 to ≦20 and m′ is an integer in the range of ≧1 to ≦20.

Preferably (m+m′) is an integer in the range of ≧3 to ≦65, morepreferably (m+m′) is an integer in the range of ≧3 to ≦50, even morepreferably (m+m′) is an integer in the range of ≧3 to ≦40.

Preferably the ratio of (m+m′) to k is in the range of 0.3:1 to 6:1,more preferably in the range of 0.3:1 to 5:1, most preferably in therange of 0.3:1 to 4:1, even more preferably in the range of 0.3:1 to3:1.

Preferably n is an integer in the range of ≧6 to ≦40 and n′ is aninteger in the range of ≧6 to ≦40, more preferably n is an integer inthe range of ≧8 to ≦35 and p′ is an integer in the range of ≧8 to ≦35.

Preferably (n+n′) is an integer in the range of ≧10 to ≦80, morepreferably (n+n′) is an integer in the range of ≧15 to ≦70.

Preferably p is an integer in the range of ≧5 to ≦25 and p′ is aninteger in the range of ≧5 to ≦25, more preferably p is an integer inthe range of ≧5 to ≦15 and p′ is an integer in the range of ≧5 to 15.

Preferably (p+p′) is an integer in the range of ≧10 to ≦30, morepreferably (p+p′) is an integer in the range of ≧15 to ≦30.

Preferably R¹ denotes an unsubstituted, linear alkyl radical having 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms. Morepreferably R¹ denotes an unsubstituted, linear alkyl radical having 8,9, 10, 11, 12, 13, 14, 15 or 16 carbon atoms. Most preferably R¹ denotesan unsubstituted, linear alkyl radical having 8, 9, 10, 11 or 12 carbonatoms.

In case the alkoxylated polytetrahydrofurane comprises units, wherein R²denotes —CH₂—CH₃, the ratio of (n+n′) to k is in the range of 1.5:1 to10:1, more preferably in the range of 1.5:1 to 6:1, most preferably inthe range of 2:1 to 5:1.

In case the alkoxylated polytetrahydrofurane comprises units, wherein R³denotes —CH₃, the ratio of (p+p′) to k is in the range of 1.2:1 to 10:1,more preferably in the range of 1.2:1 to 6:1.

In another preferred embodiment the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

-   wherein-   m is an integer in the range of ≧1 to ≦30,-   m′ is an integer in the range of ≧1 to ≦30,-   (m+m′) is an integer in the range of ≧3 to ≦50,-   n is an integer in the range of ≧3 to ≦45,-   n′ is an integer in the range of ≧3 to ≦45,-   (n+n′) is an integer in the range of ≧6 to ≦90,-   p is an integer in the range of ≧0 to ≦75,-   p′ is an integer in the range of ≧0 to ≦75,-   k is an integer in the range of ≧3 to ≦25,-   (p+p′) is an integer in the range of ≧0 to ≦30,-   k is an integer in the range of ≧3 to ≦25,-   R¹ denotes an unsubstituted, linear alkyl radical having 6, 7, 8, 9,    10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms,-   R² denotes —CH₂—CH₃, and-   R³ denotes —CH₃,    whereby the concatenations denoted by k are distributed to form a    block polymeric structure and the concatenations denoted by p, p′,    n, n′, m and m′ are distributed to form a block polymeric structure    or a random polymeric structure.

In a more preferred embodiment the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

-   wherein-   m is an integer in the range of ≧1 to ≦30,-   m′ is an integer in the range of ≧1 to ≦30,-   (m+m′) is an integer in the range of ≧3 to ≦50,-   n is an integer in the range of ≧3 to ≦45,-   n′ is an integer in the range of ≧3 to 45,-   (n+n′) is an integer in the range of ≧6 to ≦90,-   p is an integer in the range of ≧0 to ≦75,-   p′ is an integer in the range of ≧0 to ≦75,-   k is an integer in the range of ≧3 to 25,-   (p+p′) is an integer in the range of ≧0 to ≦30,-   k is an integer in the range of ≧3 to 25,-   R¹ denotes an unsubstituted, linear alkyl radical having 6, 7, 8, 9,    10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms,-   R² denotes —CH₂—CH₃, and-   R³ denotes —CH₃,    whereby the concatenations denoted by k are distributed to form a    block polymeric structure and the concatenations denoted by p, p′,    n, n′, m and m′ are distributed to form a block polymeric structure    or a random polymeric structure, wherein the ratio of (m+m′) to k is    in the range of 0.3:1 to 6:1 and the ratio of (n+n′) to k is in the    range of 1.5:1 to 10:1.

In a most preferred embodiment the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

whereinm is an integer in the range of ≧1 to ≦25,m′ is an integer in the range of ≧1 to ≦25,(m+m′) is an integer in the range of ≧3 to ≦40,n is an integer in the range of ≧6 to ≦40,n′ is an integer in the range of ≧6 to ≦40,(n+n′) is an integer in the range of ≧12 to ≦70,p is an integer in the range of ≧0 to ≦25,p′ is an integer in the range of ≧0 to ≦25,(p+p′) is an integer in the range of ≧0 to ≦30,k is an integer in the range of ≧5 to ≦20,R¹ denotes an unsubstituted, linear alkyl radical having 8, 9, 10, 11 or12 carbon atoms,R² denotes —CH₂—CH₃, andR³ denotes —CH₃,whereby the concatenations denoted by k are distributed to form a blockpolymeric structure and the concatenations denoted by p, p′, n, n′, mand m′ are distributed to form a block polymeric structure or a randompolymeric structure,wherein the ratio of (m+m′) to k is in the range of 0.3:1 to 4:1 and theratio of (n+n′) to k is in the range of 1.5:1 to 5:1.

In another preferred embodiment the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

-   wherein-   m is an integer in the range of ≧1 to ≦25,-   m′ is an integer in the range of ≧1 to ≦25,-   (m+m′) is an integer in the range of ≧3 to ≦50,-   n is an integer in the range of ≧0 to ≦45,-   n′ is an integer in the range of ≧0 to ≦45,-   (n+n′) is an integer in the range of ≧0 to ≦80,-   p is an integer in the range of ≧3 to ≦45,-   p′ is an integer in the range of ≧3 to ≦45,-   (p+p′) is an integer in the range of ≧6 to ≦90,-   k is an integer in the range of ≧3 to ≦25,-   R¹ denotes an unsubstituted, linear alkyl radical having 6, 7, 8, 9,    10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms,-   R² denotes —CH₂—CH₃, and-   R³ denotes —CH₃,    whereby the concatenations denoted by k are distributed to form a    block polymeric structure and the concatenations denoted by p, p′,    n, n′, m and m′ are distributed to form a block polymeric structure    or a random polymeric structure.

In a more preferred embodiment the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

-   wherein-   m is an integer in the range of ≧1 to ≦30,-   m′ is an integer in the range of ≧1 to ≦30,-   (m+m′) is an integer in the range of ≧3 to ≦50,-   n is an integer in the range of ≧0 to ≦45,-   n′ is an integer in the range of ≧0 to ≦45,-   (n+n′) is an integer in the range of ≧0 to ≦80,-   p is an integer in the range of ≧3 to ≦45,-   p′ is an integer in the range of ≧3 to ≦45,-   (p+p′) is an integer in the range of ≧6 to ≦90,-   k is an integer in the range of ≧3 to ≦25,-   R¹ denotes an unsubstituted, linear alkyl radical having 6, 7, 8, 9,    10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms,-   R² denotes —CH₂—CH₃, and-   R³ denotes —CH₃,    whereby the concatenations denoted by k are distributed to form a    block polymeric structure and the concatenations denoted by p, p′,    n, n′, m and m′ are distributed to form a block polymeric structure    or a random polymeric structure, wherein the ratio of (m+m′) to k is    in the range of 0.3:1 to 6:1 and the ratio of (p+p′) to k is in the    range of 1.5:1 to 10:1.

In a most preferred embodiment the presently claimed invention isdirected to the use of an alkoxylated polytetrahydrofurane of generalformula (I)

whereinm is an integer in the range of ≧1 to ≦25,m′ is an integer in the range of ≧1 to ≦25,(m+m′) is an integer in the range of ≧3 to ≦50,n is an integer in the range of ≧0 to ≦45,n′ is an integer in the range of ≧0 to ≦45,(n+n′) is an integer in the range of ≧0 to ≦80,p is an integer in the range of ≧5 to ≦20,p′ is an integer in the range of ≧5 to ≦20,(p+p′) is an integer in the range of ≧10 to ≦30,k is an integer in the range of ≧5 to ≦20,R¹ denotes an unsubstituted, linear alkyl radical having 8, 9, 10, 11 or12 carbon atoms,R² denotes —CH₂—CH₃, andR³ denotes —CH₃,whereby the concatenations denoted by k are distributed to form a blockpolymeric structure and the concatenations denoted by p, p′, n, n′, mand m′ are distributed to form a block polymeric structure or a randompolymeric structure, wherein the ratio of (m+m′) to k is in the range of0.3:1 to 4:1 and the ratio of (p+p′) to k is in the range of 1.5:1 to5:1.

The alkoxylated polytetrahydrofuranes mentioned are obtained by reactingat least one polytetrahydrofurane block polymer with at least one C₈-C₃₀epoxy alkane and optionally at least one epoxide selected from the groupconsisting of ethylene oxide, propylene oxide and butylene oxide in thepresence of at least one catalyst. In case at least one epoxide selectedfrom the group consisting of ethylene oxide, propylene oxide andbutylene oxide is used, the at least one C₈-C₃₀ epoxy alkane and the atleast one epoxide selected from the group consisting of ethylene oxide,propylene oxide and butylene oxide can either be added as a mixture ofepoxides to obtain a random copolymer or in portions, whereby eachportion contains a different epoxide, to obtain a block copolymer.

Preferably the at least one C₈-C₃₀ epoxy alkane is selected from thegroup consisting of 1,2-epoxyoctane; 1,2-epoxynonane; 1,2-epoxydecane;1,2-epoxyundecane; 1,2-epoxy-dodecane; 1,2-epoxytridecane;1,2-epoxytetradecane; 1,2-epoxypentadecane; 1,2-epoxyhexadecane;1,2-epoxyheptadecane; 1,2-epoxyoctadecane; 1,2-epoxynonade-cane;1,2-epoxyicosane; 1,2-epoxyunicosane; 1,2-epoxydocosane;1,2-epoxytricosane; 1,2-epoxytetracosane; 1,2-epoxypentacosane;1,2-epoxyhexacosane; 1,2-epoxyhepta-cosane; 1,2-epoxyoctacosane;1,2-epoxynonacosane and 1,2-epoxytriacontane.

Preferably the at least one catalyst is a base or a double metal cyanidecatalyst (DMC catalyst). More preferably the at least one catalyst isselected from the group consisting of alkaline earth metal hydroxidessuch as calcium hydroxide, strontium hydroxide and barium hydroxide,alkali metal hydroxides such as lithium hydroxide, sodium hydroxide,potassium hydroxide, rubidium hydroxide and caesium hydroxide and alkalimetal alkoxylates such as potassium tert-butoxylate. Most preferably theat least one catalyst is sodium hydroxide or potassium tert-butoxylate.Most preferably the at least one catalyst is potassium tert-butoxylate.

In case the catalyst is a base, any inert solvents capable of dissolvingalkoxylated polytetrahydrofurane and polytetrahydrofurane may be used assolvents during the reaction or as solvents required for working up thereaction mixture in cases where the reaction is carried out withoutsolvents. The following solvents are mentioned as examples: methylenechloride, trichloroethylene, tetrahydrofuran, dioxane, methyl ethylketone, methylisobutyl ketone, ethyl acetate and isobutyl acetate.

In case the catalyst is a base, the amount of catalysts used ispreferably in the range from 0.01 to 1.0, more preferably in the rangefrom 0.05 to 0.5, % by weight, based on the total amount of thealkoxylated polytetrahydrofurane. The reaction is preferably carried outat a temperature in the range of 70 to 200° C., more preferably from 100to 160° C. The pressure is preferably in the range from 1 bar to 150bar, more preferably in the range from 3 to 30 bar.

In case a DMC catalyst is used, it is in principle possible to use alltypes of DMC catalysts known from the prior art. Preference is given tousing double metal cyanide catalysts of the general formula (1):

M¹ _(a)[M²(CN)_(b)(A)_(c)]_(d) .fM¹ gX_(n) .h(H₂O).eL  (1)

whereinM¹ is a metal ion selected from the group comprising Zn²⁺, Fe²⁺, Co³⁺,Ni²⁺, Mn²⁺, Co²⁺, Sn²⁺, Pb²⁺, Mo⁴⁺, Mo⁶⁺, Al³⁺, V⁴⁺, V⁵⁺, Sr²⁺, W⁶⁺,Cr²⁺, Cr³⁺ and Cd²⁺,M² is a metal ion selected from the group comprising Fe²⁺, Fe³⁺, Co²⁺,Co³⁺, Mn²⁺, Mn³⁺, V⁴⁺, V⁵⁺, Cr²⁺, Cr³⁺, Rh³⁺, Ru²⁺ and Ir³⁺,M¹ and M² are identical or different,A is an anion selected from the group comprising halide, hydroxide,sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate,carboxylate, oxalate and nitrate,X is an anion selected from the group comprising halide, hydroxide,sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate,carboxylate, oxalate and nitrate,L is a water-miscible ligand selected from the group comprisingalcohols, aldehydes, ketones, ethers, polyethers, esters, ureas, amides,nitriles and sulfides,anda, b, c, d, g and n are selected so that the compound is electricallyneutralande is the coordination number of the ligand or zero,f is a fraction or integer greater than or equal to zero,h is a fraction or integer greater than or equal to zero.

Such compounds are generally known and can be prepared, for example, bythe process described in EP 0 862 947 B1 by combining the aqueoussolution of a water-soluble metal salt with the aqueous solution of ahexacyanometallate compound, in particular of a salt or an acid, and, ifnecessary, adding a water-soluble ligand thereto either during or afterthe combination of the two solutions.

DMC catalysts are usually prepared as a solid and used as such. Thecatalyst is typically used as powder or in suspension. However, otherways known to those skilled in the art for using catalysts can likewisebe employed. In a preferred embodiment, the DMC catalyst is dispersedwith an inert or non-inert suspension medium which can be, for example,the product to be produced or an intermediate by suitable measures, e.g.milling. The suspension produced in this way is used, if appropriateafter removal of interfering amounts of water by methods known to thoseskilled in the art, e.g. stripping with or without use of inert gasessuch as nitrogen and/or noble gases. Suitable suspension media are, forexample, toluene, xylene, tetrahydrofuran, acetone, 2-methyl-pentanone,cyclohexanone and also polyether alcohols according to the invention andmixtures thereof. The catalyst is preferably used in a suspension in apolyol as described, for example, in EP 0 090 444 A.

The present invention also provides a fuel composition which comprises,in a major amount, a gasoline fuel and, in a minor amount, at least onealkoxylated polytetra-hydrofurane of general formula (I), and at leastone fuel additive which is different from the alkoxylatedpolytetrahydrofurane (I) and has detergent action.

Typically, the amount of this at least one alkoxylatedpolytetrahydrofurane in the gaso-line fuel is 10 to 5000 ppm by weight,more preferably 20 to 2000 ppm by weight, even more preferably to 1000ppm by weight and especially 40 to 500 ppm by weight, for example 50 to300 ppm by weight.

Useful gasoline fuels include all conventional gasoline fuelcompositions. A typical representative which shall be mentioned here isthe Eurosuper base fuel to EN 228, which is customary on the market. Inaddition, gasoline fuel compositions of the specification according toWO 00/47698 are also possible fields of use for the present invention.In addition, in the context of the present invention, gasoline fuelsshall also be understood to mean alcohol-containing gasoline fuels,especially ethanol-containing gasoline fuels, as described, for example,in WO 2004/090079, for example Flex fuel with an ethanol content of 75to 85% by volume, or gasoline fuel comprising 85% by volume of ethanol(“E85”), but also the “E100” fuel type, which is typicallyazeotropi-cally distilled ethanol and thus consists of approx. 96% byvolume of C₂H₅OH and approx. 4% by volume of H₂O.

The alkoxylated polytetrahydrofurane (I) mentioned may be added to theparticular base fuel either alone or in the form of fuel additivepackages (for gasoline fuels also called “gasoline performancepackages”). Such packages are fuel additive concen-trates and generallyalso comprise, as well as solvents, and as well as the at least one fueladditive which is different from the alkoxylated polytetrahydrofurane(I) and has detergent action, a series of further components ascoadditives, which are especially carrier oils, corrosion inhibitors,demulsifiers, dehazers, antifoams, combustion improvers, antioxidants orstabilizers, antistats, metallocenes, metal deactivators, solubilizers,markers and/or dyes.

Detergents or detergent additives as the at least one fuel additivewhich is different from the alkoxylated polytetrahydrofurane (I) and hasdetergent action, referred to hereinafter as component (D), typicallyrefer to deposition inhibitors for fuels. The detergent additives arepreferably amphi-philic substances which possess at least onehydrophobic hydrocarbyl radical having a number-average molecular weight(M_(n)) of 85 to 20 000, especially of 300 to 5000, in particular of 500to 2500, and at least one polar moiety.

In a preferred embodiment, the inventive fuel composition comprises, asthe at least one fuel additive (D) which is different from thealkoxylated polytetrahydrofurane (I) and has detergent action, at leastone representative which is selected from:

-   (Da) mono- or polyamino groups having up to 6 nitrogen atoms, at    least one nitrogen atom having basic properties;-   (Db) nitro groups, optionally in combination with hydroxyl groups;-   (Dc) hydroxyl groups in combination with mono- or polyamino groups,    at least one nitrogen atom having basic properties;-   (Dd) carboxyl groups or their alkali metal or alkaline earth metal    salts;-   (De) sulfo groups or their alkali metal or alkaline earth metal    salts;-   (Df) polyoxy-C₂-C₄-alkylene moieties terminated by hydroxyl groups,    mono- or polyamino groups, at least one nitrogen atom having basic    properties, or by carbamate groups;-   (Dg) carboxylic ester groups;-   (Dh) moieties derived from succinic anhydride and having hydroxyl    and/or amino and/or amido and/or imido groups; and/or-   (Di) moieties obtained by Mannich reaction of substituted phenols    with aldehydes and mono- or polyamines.

The hydrophobic hydrocarbon radical in the above detergent additives,which ensures the adequate solubility in the fuel composition, has anumber-average molecular weight (M_(n)) of 85 to 20 000, especially of300 to 5000, in particular of 500 to 2500. Useful typical hydrophobichydrocarbyl radicals, especially in conjunction with the polar moieties(Da), (Dc), (Dh) and (Di), are relatively long-chain alkyl or alkenylgroups, especially the polypropenyl, polybutenyl and polyisobutenylradicals each having M_(n)=300 to 5000, especially 500 to 2500, inparticular 700 to 2300.

Examples of the above groups of detergent additives include thefollowing:

Additives comprising mono- or polyamino groups (Da) are preferablypolyalkenemono- or poly-alkenepolyamines based on polypropene or onhighly-reactive (i.e. having predominantly terminal double bonds in theα- and/or β-position such as vinylidene double bonds) or conventional(i.e. having predominantly internal double bonds) polybutene orpolyisobutene having M_(n)=300 to 5000. Such detergent additives basedon highly-reactive polybutene or polyisobutene, which are normallyprepared by hydroformylation of the poly(iso)butene and subsequentreductive amination with ammonia, monoamines or polyamines, are knownfrom EP-A 244 616. When the preparation of the additives proceeds frompolybutene or polyisobutene having predominantly internal double bonds(usually in the β- and/or γ-positions), one possible preparative routeis by chlorination and subsequent amination or by oxidation of thedouble bond with air or ozone to give the carbonyl or carboxyl compoundand subsequent amination under reductive (hydrogenating) conditions. Theamines used here for the amination may be, for example, ammonia,monoamines or polyamines such as dimethylaminopropylamine,ethylenediamine, diethylenetriamine, triethylenetetramine ortetraethylenepentamine. Corresponding additives based on polypropene aredescribed in particular in WO-A-94/24231.

Further preferred additives comprising monoamino groups (Da) are thehydrogenation products of the reaction products of polyisobutenes havingan average degree of polymerization P=5 to 100 with nitrogen oxides ormixtures of nitrogen oxides and oxygen, as described in particular inWO-A-97/03946.

Further preferred additives comprising monoamino groups (Da) are thecompounds obtainable from polyisobutene epoxides by reaction with aminesand subsequent dehydration and reduction of the amino alcohols, asdescribed in particular in DE-A-196 20 262.

Additives comprising nitro groups (Db), optionally in combination withhydroxyl groups, are preferably reaction products of polyisobuteneshaving an average degree of polymerization P=5 to 100 or 10 to 100 withnitrogen oxides or mixtures of nitrogen oxides and oxygen, as describedin particular in WO-A-96/03367 and in WO-A 96/03479. These reactionproducts are generally mixtures of pure nitropolyisobutenes (e.g.α,β-dinitropolyisobutene) and mixed hydroxynitropolyisobutenes (e.g.α-nitro-β-hydroxypolyisobutene).

Additives comprising hydroxyl groups in combination with mono- orpolyamino groups (Dc) are in particular reaction products ofpolyisobutene epoxides obtainable from polyisobutene having preferablypredominantly terminal double bonds and M_(n)=300 to 5000, with ammoniaor mono- or polyamines, as described in particular in EP-A-476 485.

Additives comprising carboxyl groups or their alkali metal or alkalineearth metal salts (Dd) are preferably copolymers of C₂-C₄₀-olefins withmaleic anhydride which have a total molar mass of 500 to 20 000 and someor all of whose carboxyl groups have been converted to the alkali metalor alkaline earth metal salts and any remainder of the carboxyl groupshas been reacted with alcohols or amines. Such additives are disclosedin particular by EP-A-307 815. Such additives serve mainly to preventvalve seat wear and can, as described in WO-A-87/01126, advantageouslybe used in combination with customary fuel detergents such aspoly(iso)buteneamines or polyetheramines.

Additives comprising sulfo groups or their alkali metal or alkalineearth metal salts (De) are preferably alkali metal or alkaline earthmetal salts of an alkyl sulfosuccinate, as described in particular inEP-A-639 632. Such additives serve mainly to prevent valve seat wear andcan be used advantageously in combination with customary fuel detergentssuch as poly(iso)buteneamines or polyetheramines.

Additives comprising polyoxy-C₂-C₄-alkylene moieties (Df) are preferablypolyethers or polyetheramines which are obtainable by reaction ofC₂-C₆₀-alkanols, C₆-C₃₀-alkane-diols, mono- or di-C₂-C₃₀-alkylamines,C₁-C₃₀-alkylcyclohexanols or C₁-C₃₀-alkylphenols with 1 to 30 mol ofethylene oxide and/or propylene oxide and/or butylene oxide per hydroxylgroup or amino group and, in the case of the polyetheramines, bysubsequent reductive amination with ammonia, monoamines or polyamines.Such products are described in particular in EP-A-310 875, EP-A-356 725,EP-A-700 985 and U.S. Pat. No. 4,877,416. In the case of polyethers,such products also have carrier oil properties. Typical examples ofthese are tridecanol butoxylates, isotridecanol butoxylates,isononyl-phenol butoxylates and polyisobutenol butoxylates andpropoxylates and also the corresponding reaction products with ammonia.

Additives comprising carboxylic ester groups (Dg) are preferably estersof mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, in particular those having a minimum viscosity of 2 mm²/s at100° C., as described in particular in DE-A-38 38 918. The mono-, di- ortricarboxylic acids used may be aliphatic or aromatic acids, andparticularly suitable ester alcohols or ester polyols are long-chainrepresentatives having, for example, 6 to 24 carbon atoms. Typicalrepresentatives of the esters are adipates, phthalates, isophthalates,terephthalates and trimellitates of isooctanol, of isononanol, ofisodecanol and of isotridecanol. Such products also have carrier oilproperties.

Additives comprising moieties derived from succinic anhydride and havinghydroxyl and/or amino and/or amido and/or imido groups (Dh) arepreferably corresponding derivatives of alkyl- or alkenyl-substitutedsuccinic anhydride and especially the corresponding derivatives ofpolyisobutenylsuccinic anhydride which are obtainable by reactingconventional or high-reactivity poly-isobutene having M_(n)=300 to 5000with maleic anhydride by a thermal route or via the chlorinatedpolyisobutene. Of particular interest in this context are derivativeswith aliphatic polyamines such as ethylenediamine, diethylenetriamine,triethylenetetramine or tetraethylenepentamine. The moieties havinghydroxyl and/or amino and/or amido and/or imido groups are, for example,carboxylic acid groups, acid amides of monoamines, acid amides of di- orpolyamines which, in addition to the amide function, also have freeamine groups, succinic acid derivatives having an acid and an amidefunction, carboximides with monoamines, carboximides with di- orpolyamines which, in addition to the imide function, also have freeamine groups, or diimides which are formed by the reaction of di- orpolyamines with two succinic acid derivatives. Such fuel additives aredescribed especially in U.S. Pat. No. 4,849,572.

The detergent additives from group (Dh) are preferably the reactionproducts of alkyl- or alkenyl-substituted succinic anhydrides,especially of polyisobutenylsuccinic anhydrides (“PIBSAs”), with aminesand/or alcohols. These are thus derivatives which are derived fromalkyl-, alkenyl- or polyisobutenylsuccinic anhydride and have aminoand/or amido and/or imido and/or hydroxyl groups. It is self-evidentthat these reaction products are obtainable not only when substitutedsuccinic anhydride is used, but also when substituted succinic acid orsuitable acid derivatives, such as succinyl halides or succinic esters,are used.

The additized fuel preferably comprises at least one detergent based ona polyisobutenyl-substituted succinimide. Especially of interest are theimides with aliphatic polyamines. Particularly preferred polyamines areethylenediamine, diethylenetriamine, triethylenetetramine,pentaethylenehexamine and in particular tetraethylenepentamine. Thepolyisobutenyl radical has a number-average molecular weight M_(n) ofpreferably from 500 to 5000, more preferably from 500 to 2000 and inparticular of about 1000.

Additives comprising moieties (Di) obtained by Mannich reaction ofsubstituted phenols with aldehydes and mono- or polyamines arepreferably reaction products of polyisobutene-substituted phenols withformaldehyde and mono- or polyamines such as ethylenediamine,diethylenetriamine, triethylenetetramine, tetraethylenepentamine ordimethylaminopropylamine. The polyisobutenyl-substituted phenols mayoriginate from conventional or high-reactivity poly-isobutene havingM_(n)=300 to 5000. Such “polyisobutene Mannich bases” are describedespecially in EP-A-831 141.

The inventive fuel composition comprises the at least one fuel additivewhich is different than the inventive reaction product and has detergentaction, and is normally selected from the above groups (Da) to (Di), inan amount of typically 10 to 5000 ppm by weight, more preferably of 20to 2000 ppm by weight, even more preferably of 30 to 1000 ppm by weightand especially of 40 to 500 ppm by weight, for example of 50 to 250 ppmby weight.

The detergent additives (D) mentioned are preferably used in combinationwith at least one carrier oil. In a preferred embodiment, the inventivefuel composition comprises, in addition to the at least one inventivereaction product and the at least one fuel additive which is differentthan the inventive reaction product and has detergent action, as afurther fuel additive in a minor amount, at least one carrier oil.

Suitable mineral carrier oils are the fractions obtained in crude oilprocessing, such as brightstock or base oils having viscosities, forexample, from the SN 500-2000 class; but also aromatic hydrocarbons,paraffinic hydrocarbons and alkoxyalkanols. Likewise useful is afraction which is obtained in the refining of mineral oil and is knownas “hydrocrack oil” (vacuum distillate cut having a boiling range offrom about 360 to 500° C., obtainable from natural mineral oil which hasbeen catalytically hydrogenated under high pressure and isomerized andalso deparaffinized). Likewise suitable are mixtures of abovementionedmineral carrier oils.

Examples of suitable synthetic carrier oils are selected from:polyolefins (poly-alpha-olefins or poly(internal olefin)s),(poly)esters, (poly)alkoxylates, polyethers, aliphatic polyetheramines,alkylphenol-started polyethers, alkylphenol-started polyetheramines andcarboxylic esters of long-chain alkanols.

Examples of suitable polyolefins are olefin polymers having M_(n)=from400 to 1800, in particular based on polybutene or polyisobutene(hydrogenated or unhydrogenated).

Examples of suitable polyethers or polyetheramines are preferablycompounds comprising polyoxy-C₂-C₄-alkylene moieties which areobtainable by reacting C₂-C₆₀-alkanols, C₆-C₃₀-alkanediols, mono- ordi-C₂-C₃₀-alkylamines, C₁-C₃₀-alkylcyclohexanols or C₁-C₃₀-alkylphenolswith from 1 to 30 mol of ethylene oxide and/or propylene oxide and/orbutylene oxide per hydroxyl group or amino group, and, in the case ofthe polyetheramines, by subsequent reductive amination with ammonia,monoamines or polyamines. Such products are described in particular inEP-A-310 875, EP-A-356 725, EP-A-700 985 and U.S. Pat. No. 4,877,416.For example, the polyether-amines used may be poly-C₂-C₆-alkylene oxideamines or functional derivatives thereof. Typical examples thereof aretridecanol butoxylates or isotridecanol butoxylates, isononylphenolbutoxylates and also polyisobutenol butoxylates and propoxylates, andalso the corresponding reaction products with ammonia.

Examples of carboxylic esters of long-chain alkanols are in particularesters of mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, as described in particular in DE-A-38 38 918. The mono-, di- ortricarboxylic acids used may be aliphatic or aromatic acids; suitableester alcohols or polyols are in particular long-chain representativeshaving, for example, from 6 to 24 carbon atoms. Typical representativesof the esters are adipates, phthalates, isophthalates, terephthalatesand trimellitates of isooctanol, isononanol, isodecanol andisotridecanol, for example di(n- or isotridecyl) phthalate.

Further suitable carrier oil systems are described, for example, inDE-A-38 26 608, DE-A-41 42 241, DE-A-43 09 074, EP-A-0 452 328 andEP-A-0 548 617.

Examples of particularly suitable synthetic carrier oils arealcohol-started polyethers having from about 5 to 35, for example fromabout 5 to 30, C₃-C₆-alkylene oxide units, for example selected frompropylene oxide, n-butylene oxide and isobutylene oxide units, ormixtures thereof. Nonlimiting examples of suitable starter alcohols arelong-chain alkanols or phenols substituted by long-chain alkyl in whichthe long-chain alkyl radical is in particular a straight-chain orbranched C₆-C₁₈-alkyl radical. Preferred examples include tridecanol andnonylphenol.

Further suitable synthetic carrier oils are alkoxylated alkylphenols, asdescribed in DE-A-101 02 913.

Preferred carrier oils are synthetic carrier oils, particular preferencebeing given to poly-ethers.

When a carrier oil is used in addition, it is added to the inventiveadditized fuel in an amount of preferably from 1 to 1000 ppm by weight,more preferably from 10 to 500 ppm by weight and in particular from 20to 100 ppm by weight.

In a preferred embodiment, the inventive fuel composition comprises, inaddition to the at least one inventive reaction product, the at leastone fuel additive which is different from the alkoxylatedpolytetrahydrofurane (I) mentioned and has detergent action, andoptionally the at least one carrier oil, as a further fuel additive in aminor amount at least one tertiary hydrocarbyl amine of formula NR⁴R⁵R⁶wherein R⁴, R⁵ and R⁶ are the same or different C₁- to C₂₀-hydrocarbylresidues with the proviso that the overall number of carbon atoms informula (I) does not exceed 30.

Tertiary hydrocarbyl amines have proven to be advantageous with regardto use as performance additives in fuels controlling deposits. Besidestheir superior performance behavior, they are also good to handle astheir melting points are normally low enough to be usually liquid atambient temperature.

“Hydrocarbyl residue” for R⁴ to R⁶ shall mean a residue which isessentially composed of carbon and hydrogen, however, it can contain insmall amounts heteroatomes, especially oxygen and/or nitrogen, and/orfunctional groups, e.g. hydroxyl groups and/or carboxylic groups, to anextent which does not distort the predominantly hydrocarbon character ofthe residue. Hydrocarbyl residues are preferably alkyl, alkenyl,alkinyl, cycloalkyl, aryl, alkylaryl or arylalkyl groups. Especiallypreferred hydrocarbyl residues for R⁴ to R⁶ are linear or branched alkylor alkenyl groups.

The overall number of carbon atoms in the tertiary hydrocarbyl aminementioned is at most 30, preferably at most 27, more preferably at most24, most preferably at most 20. Preferably, the minimum overall numberof carbon atoms in formula NR⁴R⁵R⁶ is 6, more preferably 8, mostpreferably 10. Such size of the tertiary hydrocarbyl amine mentionedcorresponds to molecular weight of about 100 to about 450 for thelargest range and of about 150 to about 300 for the smallest range; mostusually, tertiary hydrocarbyl amines mentioned within a molecular rangeof from 100 to 300 are used.

The three C₁- to C₂₀-hydrocarbyl residues may be identical or different.Preferably, they are different, thus creating an amine molecular whichexhibits an oleophobic moiety (i.e. the more polar amino group) and anoleophilic moiety (i.e. a hydrocarbyl residue with a longer chain lengthor a larger volume). Such amine molecules with oleophobic/oleophilicbalance have proved to show the best deposit control performanceaccording the present invention.

Preferably, a tertiary hydrocarbyl amine of formula NR⁴R⁵R⁶ is usedwherein at least two of hydrocarbyl residues R⁴, R⁵ and R⁶ are differentwith the proviso that the hydrocarbyl residue with the most carbon atomsdiffer in carbon atom number from the hydrocarbyl residue with thesecond most carbon atoms in at least 3, preferably in at least 4, morepreferably in at least 6, most preferably in at least 8. Thus, thetertiary amines mentioned exhibit hydrocarbyl residues of two or threedifferent chain length or different volume, respectively.

Still more preferably, a tertiary hydrocarbyl amine of formula NR⁴R⁵R⁶is used wherein one or two of R⁴ to R⁶ are C₇- to C₂₀-hydrocarbylresidues and the remaining two or one of R⁴ to R⁶ are C₁- toC₄-hydrocarbyl residues.

The one or the two longer hydrocarbyl residues, which may be in case oftwo residues identical or different, exhibit from 7 to 20, preferablyfrom 8 to 18, more preferably from 9 to 16, most preferably from 10 to14 carbon atoms. The one or the two remaining shorter hydrocarbylresidues, which may be in case of two residues identical or different,exhibit from 1 to 4, preferably from 1 to 3, more preferably 1 or 2,most preferably 1 carbon atom(s). Besides the desired depositcontrolling performance, the oleophilic long-chain hydrocarbyl residuesprovide further advantageous properties to the tertiary amines, i.e.high solubility for gasoline fuels and low volatility.

More preferably, tertiary hydrocarbyl amines of formula NR⁴R⁵R⁶ areused, wherein R⁴ is a C₈-to C₁₈-hydrocarbyl residue and R⁵ and R⁶ areindependently of each other C₁- to C₄-alkyl radicals. Still morepreferably, tertiary hydrocarbyl amines of formula NR⁴R⁵R⁶ are used,wherein R⁴ is a C₉- to C₁₆-hydrocarbyl residue and R⁵ and R⁶ are bothmethyl radicals.

Examples for suitable linear or branched C₁- to C₂₀-alkyl residues forR⁴ to R⁶ are: methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,sec.-butyl, tert-butyl, n-pentyl, tert-pentyl, 2-methylbutyl,3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, n-hexyl,2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl,1,2-dimethylbutyl, 1,3-dimethylbutyl, 2-ethylbutyl, n-heptyl,1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl,5-methylhexyl, 1,1-dimethylpentyl, 1,2-dimethylpentyl,2,2-dimethylpentyl, 2,3-dimethylpentyl, 2,4-dime-thylpentyl,2,5-dimethylpentyl, 2-diethylpentyl, 3-diethyl-pentyl, n-octyl,1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 4-methylheptyl,5-methylheptyl, 6-methylheptyl, 1,1-dimethylhexyl, 1,2-dimethylhexyl,2,2-dimethylhexyl, 2,3-dimethylhexyl, 2,4-dimethyl-hexyl,2,5-dimethylhexyl, 2,6-dimethylhexyl, 2-ethyl-hexyl, 3-ethylhexyl,4-ethylhexyl, n-nonyl, iso-nonyl, n-decyl, 1-propylheptyl,2-propyl-heptyl, 3-propylheptyl, n-undecyl, n-dodecyl, n-tridecyl,iso-tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,nonadecyl and eicosyl.

Examples for suitable linear or branched C₂- to C₂₀-alkenyl and -alkinylresidues for R⁴ to R⁶ are: vinyl, allyl, oleyl and propin-2-yl.

Tertiary hydrocarbyl amines of formula NR⁴R⁵R⁶ with long-chain alkyl andalkenyl residues can also preferably be obtained or derived from naturalsources, i.e. from plant or animal oils and lards. The fatty aminesderived from such sources which are suitable as such tertiaryhydrocarbyl amines normally form mixtures of different similar speciessuch as homologues, e.g. tallow amines containing as main componentstetradecyl amine, hexadecyl amine, octadecyl amine and octadecenyl amine(oleyl amine). Further examples of suitable fatty amines are: co-coamines and palm amines. Unsaturated fatty amines which contain alkenylresidues can be hydrogenated und used in this saturated form.

Examples for suitable C₃- to C₂₀-cycloalkyl residues for R⁴ to R⁶ are:cyclopropyl, cyclobutyl, 2-methylcyclohexyl, 3-methylcyclohexyl,4-methylcyclohexyl, 2,3-dimethyl-cyclohexyl, 2,4-dimethylcyclohexyl,2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl,3,5-dimethylcyclohexyl, 2-ethylcyclohexyl, 3-ethylcyclohexyl,4-ethylcyclohexyl, cyclooctyl and cyclodecyl.

Examples for suitable C₇- to C₂₀-aryl, -alkylaryl or -arylalkyl residuesfor R⁴ to R⁶ are: naphthyl, tolyl, xylyl, n-octylphenyl, n-nonylphenyl,n-decylphenyl, benzyl, 1-phenyl-ethyl, 2-phenylethyl, 3-phenylpropyl and4-butylphenyl.

Typical examples for suitable tertiary hydrocarbyl amines of formulaNR⁴R⁵R⁶ are the following:

N,N-dimethyl-n-butylamine, N,N-dimethyl-n-pentylamine,N,N-dimethyl-n-hexylamine, N,N-dimethyl-n-heptylamine,N,N-dimethyl-n-octylamine, N,N-dimethyl-2-ethylhexyl-amine,N,N-di-methyl-n-nonylamine, N,N-dimethyl-iso-nonylamine,N,N-dimethyl-n-decylamine, N,N-dimethyl-2-propylheptylamine,N,N-dimethyl-n-undecylamine, N,N-dimethyl-n-dodecylamine,N,N-dimethyl-n-tridecylamine, N,N-dimethyl-iso-tridecyl-amine,N,N-dimethyl-n-tetradecylamine, N,N-dimethyl-n-hexadecylamine,N,N-di-methyl-n-octadecylamine, N,N-dimethyl-eicosylamine,N,N-dimethyl-oleylamine;

N,N-diethyl-n-heptylamine, N,N-diethyl-n-octylamine,N,N-diethyl-2-ethylhexylamine, N,N-diethyl-n-nonylamine,N,N-diethyl-iso-nonylamine, N,N-diethyl-n-decylamine,N,N-diethyl-2-propylheptylamine, N,N-diethyl-n-undecylamine,N,N-diethyl-n-dodecylamine, N,N-diethyl-n-tridecylamine,N,N-diethyl-iso-tridecylamine, N,N-diethyl-n-tetradecyl-amine,N,N-diethyl-n-hexadecylamine, N,N-di-ethyl-n-octadecylamine,N,N-diethyl-eicosylamine, N,N-diethyl-oleylamine;

N,N-di-(n-propyl)-n-heptylamine, N,N-di-(n-propyl)-n-octylamine,N,N-di-(n-propyl)-2-ethylhexylamine, N,N-di-(n-propyl)-n-nonylamine,N,N-di-(n-propyl)-iso-nonylamine, N,N-di-(n-propyl)-n-decylamine,N,N-di-(n-propyl)-2-propylheptylamine, N,N-di-(n-propyl)-n-undecylamine,N, N-di-(n-propyl)-n-dodecylamine, N, N-di-(n-propyl)-n-tri-decylamine,N, N-di-(n-propyl)-iso-tridecylamine,N,N-di-(n-propyl)-n-tetradecylamine, N,N-di-(n-propyl)-n-hexadecylamine,N,N-di-(n-propyl)-n-octadecylamine, N,N-di-(n-propyl)-eicosylamine,N,N-di-(n-propyl)-oleylamine;

N,N-di-(n-butyl)-n-heptylamine, N,N-di-(n-butyl)-n-octylamine,N,N-di-(n-butyl)-2-ethylhexylamine, N,N-di-(n-butyl)-n-nonylamine,N,N-di-(n-butyl)-iso-nonylamine, N,N-di-(n-butyl)-n-decylamine,N,N-di-(n-butyl)-2-propylheptylamine, N,N-di-(n-butyl)-n-undecyl-amine,N,N-di-(n-butyl)-n-dodecylamine, N,N-di-(n-butyl)-n-tridecylamine,N,N-di-(n-butyl)-iso-tridecylamine, N,N-di-(n-butyl)-n-tetradecylamine,N,N-di-(n-butyl)-n-hexa-decylamine, N,N-di-(n-butyl)-n-octadecylamine,N,N-di-(n-butyl)-eicosylamine, N,N-di-(n-butyl)-oleyl-amine;

N-methyl-N-ethyl-n-heptylamine, N-methyl-N-ethyl-n-octylamine,N-methyl-N-ethyl-2-ethylhexylamine, N-methyl-N-ethyl-n-nonylamine,N-methyl-N-ethyl-iso-nonylamine, N-methyl-N-ethyl-n-decylamine,N-methyl-N-ethyl-2-propylheptylamine, N-methyl-N-ethyl-n-undecylamine,N-methyl-N-ethyl-n-dodecylamine, N-methyl-N-ethyl-n-tridecylamine,N-methyl-N-ethyl-iso-tridecylamine, N-methyl-N-ethyl-n-tetradecylamine,N-methyl-N-ethyl-n-hexadecylamine, N-methyl-N-ethyl-n-octadecylamine,N-methyl-N-ethyl-eicosyl-amine, N-methyl-N-ethyl-oleylamine;

N-methyl-N-(n-propyl)-n-heptylamine, N-methyl-N-(n-propyl)-n-octylamine,N-methyl-N-(n-propyl)-2-ethylhexylamine,N-methyl-N-(n-propyl)-n-nonylamine,N-methyl-N-(n-propyl)-iso-nonylamine,N-methyl-N-(n-propyl)-n-decylamine,N-methyl-N-(n-propyl)-2-propylheptylamine,N-methyl-N-(n-propyl)-n-undecylamine,N-methyl-N-(n-propyl)-n-dodecylamine,N-methyl-N-(n-propyl)-n-tridecylamine,N-methyl-N-(n-propyl)-iso-tri-decylamine,N-methyl-N-(n-propyl)-n-tetradecylamine,N-methyl-N-(n-propyl)-n-hexa-decylamine,N-methyl-N-(n-propyl)-n-octadecylamine,N-methyl-N-(n-propyl)-eicosyl-amine, N-methyl-N-(n-propyl)-oleylamine;

N-methyl-N-(n-butyl)-n-heptylamine, N-methyl-N-(n-butyl)-n-octylamine,N-methyl-N-(n-butyl)-2-ethylhexylamine,N-methyl-N-(n-butyl)-n-nonylamine, N-methyl-N-(n-butyl)-iso-nonylamine,N-methyl-N-(n-butyl)-n-decylamine,N-methyl-N-(n-butyl)-2-propylheptyl-amine,N-methyl-N-(n-butyl)-n-undecylamine,N-methyl-N-(n-butyl)-n-dodecylamine,N-methyl-N-(n-butyl)-n-tridecylamine,N-methyl-N-(n-butyl)-iso-tridecylamine,N-methyl-N-(n-butyl)-n-tetradecylamine,N-methyl-N-(n-butyl)-n-hexadecylamine,N-methyl-N-(n-butyl)-n-octadecylamine,N-methyl-N-(n-butyl)-eicosylamine, N-methyl-N-(n-butyl)-oleylamine;

N-methyl-N,N-di-(n-heptyl)-amine, N-methyl-N,N-di-(n-octyl)-amine,N-methyl-N,N-di-(2-ethylhexyl)-amine, N-methyl-N,N-di-(n-nonyl)-amine,N-methyl-N,N-di-(iso-nonyl)-amine, N-methyl-N,N-di-(n-decyl)-amine,N-methyl-N,N-di-(2-propylheptyl)-amine,N-methyl-N,N-di-(n-undecyl)-amine, N-methyl-N,N-di-(n-dodecyl)-amine,N-methyl-N,N-di-(n-tridecyl)-amine, N-methyl-N,N-di-(iso-tridecyl)-amine, N-methyl-N, N-di-(n-tetra-decyl)-amine;

N-ethyl-N,N-di-(n-heptyl)-amine, N-ethyl-N,N-di-(n-octyl)-amine,N-ethyl-N,N-di-(2-ethylhexyl)-amine, N-ethyl-N,N-di-(n-nonyl)-amine,N-ethyl-N,N-di-(iso-nonyl)-amine, N-ethyl-N,N-di-(n-decyl)-amine,N-ethyl-N,N-di-(2-propylheptyl)-amine, N-ethyl-N,N-di-(n-undecyl)-amine,N-ethyl-N,N-di-(n-dodecyl)-amine, N-ethyl-N,N-di-(n-tridecyl)-amine,N-ethyl-N,N-di-(iso-tridecyl)-amine,N-ethyl-N,N-di-(n-tetradecyl)-amine;

N-(n-butyl)-N,N-di-(n-heptyl)-amine, N-(n-butyl)-N,N-di-(n-octyl)-amine,N-(n-butyl)-N,N-di-(2-ethylhexyl)-amine,N-(n-butyl)-N,N-di-(n-nonyl)-amine,N-(n-butyl)-N,N-di-(iso-nonyl)-amine,N-(n-butyl)-N,N-di-(n-decyl)-amine,N-(n-butyl)-N,N-di-(2-propylheptyl)-amine,N-(n-butyl)-N,N-di-(n-undecyl)-amine,N-(n-butyl)-N,N-di-(n-dodecyl)-amine,N-(n-butyl)-N,N-di-(n-tridecyl)-amine,N-(n-butyl)-N,N-di-(iso-tridecyl)-amine;

N-methyl-N-(n-heptyl)-N-(n-dodecyl)-amine,N-methyl-N-(n-heptyl)-N-(n-octadecyl)-amine,N-methyl-N-(n-octyl)-N-(2-ethylhexyl)-amine,N-methyl-N-(2-ethylhexyl)-N-(n-dodecyl)-amine,N-methyl-N-(2-propylheptyl)-N-(n-undecyl)-amine,N-methyl-N-(n-decyl)-N-(n-dodecyl)-amine,N-methyl-N-(n-decyl)-N-(-tetradecyl)-amine,N-methyl-N-(n-decyl)-N-(n-hexadecyl)-amine,N-methyl-N-(n-decyl)-N-(n-octadecyl)-amine,N-methyl-N-(n-decyl)-N-oleylamine,N-methyl-N-(n-dodecyl)-N-(iso-tridecyl)-amine,N-methyl-N-(n-dodecyl)-N-(n-tetradecyl)-amine,N-methyl-N-(n-dodecyl)-N-(n-hexa-decyl)-amine,N-methyl-N-(n-dodecyl)-oleylamine;

Also suitable tertiary hydrocarbyl amines of formula NR⁴R⁵R⁶ aremonocyclic structures, wherein one of the short-chain hydrocarbylresidue forms with the nitrogen atom and with the other short-chainhydrocarbyl residue a five- or six-membered ring. Oxygen atoms and/orfurther nitrogen atoms may additionally be present in such five- orsix-membered ring. In each case, such cyclic tertiary amines carry atthe nitrogen atom or at one of the nitrogen atoms, respectively, thelong-chain C₇- to C₂₀-hydrocarbyl residue. Examples for such monocyclictertiary amines are N—(C₇- to C₂₀-hydrocarbyl)-piperidines, N—(C₇- toC₂₀-hydrocarbyl)-piperazines and N—(C₇- to C₂₀-hydrocarbyl)-morpholines.

The inventive fuel composition may comprise further customarycoadditives, as described below:

Corrosion inhibitors suitable as such coadditives are, for example,succinic esters, in particular with polyols, fatty acid derivatives, forexample oleic esters, oligomerized fatty acids and substitutedethanolamines.

Demulsifiers suitable as further coadditives are, for example, thealkali metal and alkaline earth metal salts of alkyl-substituted phenol-and naphthalenesulfonates and the alkali metal and alkaline earth metalsalts of fatty acid, and also alcohol alkoxylates, e.g. alcoholethoxylates, phenol alkoxylates, e.g. tert-butylphenol ethoxylates ortert-pentylphenol ethoxylates, fatty acid, alkylphenols, condensationproducts of ethylene oxide and propylene oxide, e.g. ethyleneoxide-propylene oxide block copolymers, polyethyleneimines andpolysiloxanes.

Dehazers suitable as further coadditives are, for example, alkoxylatedphenol-formaldehyde condensates.

Antifoams suitable as further coadditives are, for example,polyether-modified polysiloxanes.

Antioxidants suitable as further coadditives are, for example,substituted phenols, e.g. 2,6-di-tert-butylphenol and2,6-di-tert-butyl-3-methylphenol, and also phenylenediamines, e.g.N,N′-di-sec-butyl-p-phenylenediamine.

Metal deactivators suitable as further coadditives are, for example,salicylic acid derivatives, e.g. N,N′-disalicylidene-1,2-propanediamine.

Suitable solvents, especially also for fuel additive packages, are, forexample, nonpolar organic solvents, especially aromatic and aliphatichydrocarbons, for example toluene, xylenes, “white spirit” and thetechnical solvent mixtures of the designations Shellsol® (manufacturer:Royal Dutch/Shell Group), Exxol® (manufacturer: ExxonMobil) and SolventNaphtha. Also useful here, especially in a blend with the nonpolarorganic solvents mentioned, are polar organic solvents, in particularalcohols such as tert-butanol, isoamyl alcohol, 2-ethylhexanol and2-propylheptanol.

When the coadditives and/or solvents mentioned are used in addition ingasoline fuel, they are used in the amounts customary therefor.

In an especially preferred embodiment, as the at least one fuel additive(D) to be used together with the alkoxylated polytetrahydrofurane (I)mentioned which is different from the said alkoxylatedpolytetrahydrofuran and has detergent action is selected from (Da)polyisobutene monoamines or polyisobutene polyamines having M_(n)=300 to5000, having predominantly vinylidene double bonds (normally at least 50mol-% of vinylidene double bonds, especially at least 70 mol-% ofvinylidene double bonds) and having been prepared by hydroformylation ofthe respective polyisobutene and subsequent reductive amination withammonia, monoamines or polyamines. Such polyisobutene monoamines andpolyisobutene polyamines are preferably applied in combination with atleast one mineral or synthetic carrier oil, more preferably incombination with at least one polyether-based or polyetheramine-basedcarrier oil, most preferably in combination with at least oneC₆-C₁₈-alcohol-started polyether having from about 5 to 35C₃-C₆-alkylene oxide units, especially selected from propylene oxide,n-butylene oxide and isobutylene oxide units, as described above.

The present invention also provides an additive concentrate whichcomprises at least one alkoxylated polytetrahydrofurane of generalformula (I), and at least one fuel additive which is different from thealkoxylated polytetrahydrofurane (I) and has detergent action.Otherwise, the inventive additive concentrate may comprise the furthercoadditives mentioned above. In case of additive concentrates forgasoline fuels, such additive concentrates are also called gasolineperformance packages.

The alkoxylated polytetrahydrofurane (I) mentioned is present in theinventive additive concentrate preferably in an amount of 1 to 99% byweight, more preferably of 15 to 95% by weight and especially of 30 to90% by weight, based in each case on the total weight of theconcentrate. The at least one fuel additive which is different from thealkoxylated polytetrahydrofurane (I) mentioned and has detergent actionis present in the inventive additive concentrate preferably in an amountof 1 to 99% by weight, more preferably of 5 to 85% by weight andespecially of 10 to 70% by weight, based in each case on the totalweight of the concentrate.

The alkoxylated polytetrahydrofurane (I) mentioned provides for quite aseries of advantages and unexpected performance and handlingimprovements in view of the respective solutions proposed in the art.Effective fuel saving in the operation of a spark-ignited internalcombustion engine is achieved. The respective fuel additive concentratesremain homogeneously stable over a prolonged period without any phaseseparation and/or precipitates. Miscibility with other fuel additives isimproved and the tendency to form emulsions with water is suppressed.The high level of intake valve and combustion chamber cleanlinessachieved by the modern fuel additives is not being worsened by thepresence of the alkoxylated polytetrahydrofurane (I) mentioned in thefuel. Power loss in internal combustion engines is minimized andacceleration of internal combustion engines is improved. The presence ofthe alkoxylated polytetra-hydrofurane (I) mentioned in the fuel alsoprovides for an improved lubricating perfor-mance of the lubricatingoils in the internal combustion engine.

The examples which follow are intended to further illustrate the presentinvention without restricting it.

EXAMPLES Example 1 Preparation of an Alkoxylated Polytetrahydrofuranefrom Polytetrahydrofurane 650 with 12 Equivalents of C₁₂-Epoxide and 20Equivalents of Butylene Oxide (Block)

A steel reactor (1.5 l) was loaded with polytetrahydrofurane (MW 250)(0.2 mol, 130 g), and 3.4 g KOtBu was mixed and the reactor was purgedwith nitrogen. The reactor was heated under vacuum (10 mbar) and heatedto 140° C. for 0.25 h. Then again nitrogen was loaded. At a pressure of2 bar 50 g C₁₂-epoxide was brought in dropwise at 140° C. 390 gC₁₂-epoxide of total (441 g; 2.4 mol) was added during 5 h at 140° C.and under pressure of 6 bar. Then butylene oxide (288 g, 4.0 mol) wasadded within 4 h at 140° C. The reactor was stirred for 10 h at 140° C.and cooled to 80° C. The product was stripped by nitrogen. Then theproduct was discharged and mixed with Ambosol® (magnesium silicate, 30g) and mixed on a rotary evaporator at 80° C. The purified product wasobtained by filtration in a pressure strainer (Filtrations media: Seitz900). Yield: 866 g, quantitative (theor.: 859 g) OHZ: 30.1 mg KOH/g.

Example 2 Preparation of a Gasoline Performance Package

400 mg/kg of the alkoxylated polytetrahydrofurane of Example 1 abovewere mixed with a gasoline performance package comprising the customarydetergent additive Kerocom® PIBA (a polyisobutene monoamine made by BASFSE, based on a poly-isobutene with M_(n)=1000), a customarypolyether-based carrier oil, kerosene as a diluent and a customarycorrosion inhibitor in customary amounts.

Example 3 Fuel Economy Tests

A typical Eurosuper base fuel to EN 228 customary on the European marketwas additized with the gasoline performance package of Example 2 in thedosage rate specified there and used to determine fuel economy in afleet test with three different automobiles according to U.S.Environmental Protection Agency Test Protocol, C.F.R. Title 40, Part600, Subpart B. For each automobile, the fuel consumption wasdeter-mined first with unadditized fuel and then with the same fuelwhich now, however, comprised the gasoline performance package ofExample 2 in the dosage specified there. The following fuel savings wereachieved:

-   -   2004 Mazda 3, 2.0 L I4: 2.00%;    -   Honda Civic, 1.8 L I4: 0.95%;    -   2010 Chevy HRR, 2.2 L I4: 0.66%

On average, over all automobiles used, the result was an average fuelsaving of 1.20%.

Example 4 Engine Cleanliness Tests

In order to demonstrate that the alkoxylated polytetrahydrofuranes (I)mentioned do not decrease engine cleanliness, the average IVD values andthe TCD values were deter-mined with gasoline performance package ofExample 2 (“GPP 1”) and, for compare-son, with the same gasolineperformance package without the alkoxylated polytetra-hydrofurane ofExample 1 (“GPP 2”), according to CEC F-20-98 with a Mercedes Benz M111E engine using a customary RON 95 E10 gasoline fuel and a customaryRL-223/5 engine oil. The following table shows the results of thedeterminations:

Additive average IVD [mg/valve] TCD [mg] None 118 2852 GPP 1 3 4582 GPP2 12 4433

Example 5 Storage Stability

48.0% by weight of GPP 2 above were mixed with 14.3% by weight ofalkoxylated polytetrahydrofurane of Example 1 and 37.7% by weight ofxylene at 20° C. and stored thereafter in a sealed glass bottle at −20°C. for 42 days. At the beginning of this storage period and then aftereach 7 days, the mixture was evaluated visually and checked for possiblephase separation and precipitation. It is the aim that the mixtureremains clear (“c”), homogeneous (“h”) and liquid (“l”) after storageand does not exhibit any phase separation (“ps”) or precipitation(“pr”). The following table shows the results of the evaluations:

after 7 days c, h, l after 14 days c, h, l after 21 days c, h, l after28 days c, h, l after 35 days c, h, l after 42 days c, h, l Result: pass

1: A method for reducing fuel consumption in operating an internalcombustion engine with a fuel, the method comprising: introducing analkoxylated polytetrahydrofurane of general formula (I)

into the fuel as an additive, wherein m is an integer in the range of ≧1to ≦50, m′ is an integer in the range of ≧1 to ≦50, (m+m′) is an integerin the range of ≧1 to ≦90, n is an integer in the range of ≧0 to ≦75, n′is an integer in the range of ≧0 to ≦75, p is an integer in the range of≧0 to ≦75, p′ is an integer in the range of ≧0 to ≦75, k is an integerin the range of ≧2 to ≦30, R¹ denotes an unsubstituted, linear orbranched, alkyl radical having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 or 28 carbon atoms, R²denotes —CH2-CH3, and R³ identical or different, denotes a hydrogen atomor —CH3, whereby the concatenations denoted by k are distributed to forma block polymeric structure and the concatenations denoted by p, p′, n,n′, m and m′ are distributed to form a block polymeric structure or arandom polymeric structure. 2: The method as described in claim 1,wherein the additive minimizes power loss in the internal combustionengine and improves acceleration of the internal combustion engine. 3:The method as described in claim 1, wherein the additive improves thelubricity of lubricant oils contained in the internal combustion enginefor lubricating purposes by operating the internal combustion enginewith the fuel containing an effective amount of at least one alkoxylatedpolytetrahydrofurane of formula (I). 4: The method according to claim 1,wherein k is an integer in the range of ≧3 to ≦25. 5: The methodaccording to claim 1, wherein the alkoxylated polytetrahydrofurane has aweight average molecular weight Mw in the range of 500 to 20000 g/moldetermined according to DIN 55672-1 (polystyrene calibration standard).6: The method according to claim 1, wherein (m+m′) is in the range of ≧3to ≦65. 7: The method according to claim 1, wherein the ratio of (m+m′)to k is in the range of 0.3:1 to 6:1. 8: The method according to claim1, wherein m is an integer in the range of ≧1 to ≦25 and m′ is aninteger in the range of ≧1 to ≦25. 9: The method according to claim 1,wherein R¹ denotes an unsubstituted, linear alkyl radical having 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms. 10: The methodaccording to claim 1, wherein R³ denotes —CH₃. 11: The method accordingto claim 1, wherein m is an integer in the range of ≧1 to ≦30, m′ is aninteger in the range of ≧1 to ≦30, (m+m′) is an integer in the range of≧3 to ≦50, n is an integer in the range of ≧3 to ≦45, n′ is an integerin the range of ≧3 to ≦45, (n+n′) is an integer in the range of ≧6 to≦90, p is an integer in the range of ≧0 to ≦75, p′ is an integer in therange of ≧0 to ≦75, k is an integer in the range of ≧3 to ≦25, R¹denotes an unsubstituted, linear or branched, alkyl radical having 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms, R² denotes—CH₂—CH₃, and R³ denotes —CH₃. 12: The method according to claim 11,wherein the ratio of (m+m′) to k is in the range of 0.3:1 to 6:1 and theratio of (n+n′) to k is in the range of 1.5:1 to 10:1. 13: The methodaccording to claim 1, wherein m is an integer in the range of ≧1 to ≦30,m′ is an integer in the range of ≧1 to ≦30, (m+m′) is an integer in therange of ≧3 to ≦50, n is an integer in the range of ≧0 to ≦45, n′ is aninteger in the range of ≧0 to ≦45, p is an integer in the range of ≧3 to≦45, p′ is an integer in the range of ≧3 to ≦45, (p+p′) is an integer inthe range of ≧6 to ≦90, k is an integer in the range of ≧3 to ≦25, R¹denotes an unsubstituted, linear or branched, alkyl radical having 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms, R² denotes—CH₂—CH₃, and R³ denotes —CH₃. 14: The method according to claim 13,wherein the ratio of (m+m′) to k is in the range of 0.3:1 to 6:1 and theratio of (p+p′) to k is in the range of 1.5:1 to 10:1. 15: A fuelcomposition comprising, in a major amount, a gasoline fuel and, in aminor amount, at least one alkoxylated polytetrahydrofurane of generalformula (I), and at least one fuel additive which is different from thealkoxylated polytetrahydrofurane (I) and has detergent action,

wherein m is an integer in the range of ≧1 to ≦50, m′ is an integer inthe range of ≧1 to ≦50, (m+m′) is an integer in the range of ≧1 to ≦90,n is an integer in the range of ≧0 to ≦75, n′ is an integer in the rangeof ≧0 to ≦75, p is an integer in the range of ≧0 to ≦75, p′ is aninteger in the range of ≧0 to ≦75, k is an integer in the range of ≧2 to≦30, R¹ denotes an unsubstituted, linear or branched, alkyl radicalhaving 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27 or 28 carbon atoms, R² denotes —CH2-CH3, and R³identical or different, denotes a hydrogen atom or —CH3, whereby theconcatenations denoted by k are distributed to form a block polymericstructure and the concatenations denoted by p, p′, n, n′, m and m′ aredistributed to form a block polymeric structure or a random polymericstructure. 16: The fuel composition according to claim 15 comprising, asthe fuel additive which is different from the alkoxylatedpolytetrahydrofuran (I) and has detergent action, at least onerepresentative (D) selected from the group consisting of: (Da) a mono-or polyamino group having up to 6 nitrogen atoms, at least one nitrogenatom having basic properties; (Db) a nitro group, optionally incombination with at least one hydroxyl group; (Dc) a hydroxyl group incombination with at least one mono- or polyamino group, at least onenitrogen atom having basic properties; (Dd) a carboxyl group or analkali metal or an alkaline earth metal salt thereof; (De) a sulfonicacid group or an alkali metal or an alkaline earth metal salt thereof;(Df) a polyoxy-C₂-C₄-alkylene moiety terminated by at least one hydroxylgroup, at least one mono- or polyamino group, at least one nitrogen atomhaving basic properties, or by at least one carbamate group; (Dg) acarboxylic ester group; (Dh) a moiety derived from succinic anhydrideand having at least one hydroxyl and/or amino and/or amido and/or imidogroup; and/or (Di) a moiety obtained by Mannich reaction of at least onesubstituted phenol with at least one aldehyde and at least one mono- orpolyamine. 17: The fuel composition according to claim 15, additionallycomprising, as a further fuel additive in a minor amount, at least onecarrier oil. 18: The fuel composition according to claim 15,additionally comprising, as a further fuel additive in a minor amount,at least one tertiary hydrocarbyl amine of formula NR⁴R⁵R⁶ wherein R⁴,R⁵ and R⁶ are the same or different C₁- to C₂₀-hydrocarbyl residues withthe proviso that the overall number of carbon atoms in formula (I) doesnot exceed
 30. 19: The fuel composition according to claim 16,comprising at least one representative (D) which is (Da), which is apolyisobutene monoamine or a polyisobutene polyamine having M_(n)=300 to5000, having at least 50 mol-% of vinylidene double bonds and havingbeen prepared by hydroformylation of the respective polyisobutene andsubsequent reductive amination with ammonia, monoamines or polyamines,in combination with at least one mineral or synthetic carrier oil. 20:An additive concentrate, comprising at least one alkoxylatedpolytetrahydrofurane of general formula (I), and at least one fueladditive which is different from the alkoxylated polytetrahydrofurane(I) and has detergent action,

wherein m is an integer in the range of ≧1 to ≦50, m′ is an integer inthe range of ≧1 to ≦50, (m+m′) is an integer in the range of ≧1 to ≦90,n is an integer in the range of ≧0 to ≦75, n′ is an integer in the rangeof ≧0 to ≦75, p is an integer in the range of ≧0 to ≦75, p′ is aninteger in the range of ≧0 to ≦75, k is an integer in the range of ≧2 to≦30, R¹ denotes an unsubstituted, linear or branched, alkyl radicalhaving 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27 or 28 carbon atoms, R² denotes —CH2-CH3, and R³identical or different, denotes a hydrogen atom or —CH3, whereby theconcatenations denoted by k are distributed to form a block polymericstructure and the concatenations denoted by p, p′, n, n′, m and m′ aredistributed to form a block polymeric structure or a random polymericstructure. 21: The additive concentrate according to claim 20,comprising at least one representative (Da), which is a polyisobutenemonoamine or polyisobutene polyamine having M_(n)=300 to 5000, having atleast 50 mol-% of vinylidene double bonds and having been prepared byhydroformylation of the respective polyisobutene and subsequentreductive amination with ammonia, monoamines or polyamines, and furthercomprising at least one mineral or synthetic carrier oil.